[postgis-users] TopologyException : another example.

[Guillaume Sueur]

Hi list,

I think I've got a good example of TopologyException too.
I try to aggregate my cities boundaries on a district field to get 
districts boundaries. The geom of cities is valid (set as a constraint). 
When I run the simple query "CREATE TABLE districts as SELECT 
iddistrict, geomUnion(the_geom) from cities, if gives back :
NOTICE:  TopologyException: no outgoing dirEdge found (436814,2.01401e+06)
ERROR:  GEOS union() threw an error!

Taken individually, my district build fine until some specific case :
when a city and another one to merge with are only sharing one point. I 
think the module tries to do a unique shape then, which gives a non vaid 
geometry, instead of building two distinct parts.

What do you think ?

Thanks
-- 
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Guillaume SUEUR
GEOSIGNAL - Groupe BVA
25bis Avenue Marcel Dassault
31505 TOULOUSE CEDEX 5
05 61 17 47 17
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